Astronomy: X Rays from Scorpio

Ever since 1949, when X rays from the sun
were first detected, astronomers have been probing the skies for other
X-ray sources outside the solar system.
Their search was not rewarded until 1962, when more sensitive
instruments picked up the first X-ray emissions from outside the solar
system. But until this year, only one additional visible object had
been definitely identified as an X-ray producer: the familiar Crab
Nebula.* Though their relatively crude instruments sensed X rays from
about two dozen other vaguely defined areas of the sky, astronomers
have been un able to tell which, if any, of...